1. Field of the Invention
This invention relates to an electric telpher with non-contact power transmission between a feeder arranged at a spacing along a slide rail for mobile transfer units and an inductive current collector on the transfer unit as well as with non-contact data transmission between a central control station and a controller installed on the transfer unit.
2. Background Art
In a known electric telpher system of this type, the return conductor for the feeder that is connected to a higher-frequency AC power source is the slide rail for the mobile transfer units that are equipped with a drive unit and a controller. The current collector is a ferrite core that encompasses the feeder in a U-shape with windings attached to its limbs designed for producing different feed voltages for the drive unit and the controller of the mobile transfer unit, respectively.
The initial proposal made here to also use the feeder for communication to program and remote-control the transfer units from a central control station is not feasible in practice because there is a very small signal-to-noise ratio due to the high current in the feeder and the accordingly high field density and because eliminating the resulting problems would require an unjustifiably great electrical and electronic effort.
Infrared technology is another option for non-contact data transmission in electric telpher systems. However, a data transmission system designed on this basis has spatial constraints. Data can only be transmitted from specific, locally separated points. In the meantime the transfer units are uncontrolled and cannot be influenced from outside. Reducing the distance between these communication points requires great expenditure, however.
It has also been proposed to use radio technology for data transmission; each transfer unit is equipped with a radio module and a group of overlapping radio cells is set up along the track between which the transfer units are handed over. The disadvantage of this technology is that radio contact can be impaired or lost due to external factors. Also, transfer from one radio station to another requires a major information technology effort.
It is the problem of this invention to develop a non-contact data communication system for an electric telpher with non-contact power transmission of the type mentioned above that ensures permanent central collection of information from the mobile transfer units and data transfer to control the operation of the mobile transfer units in a cost-efficient way and also guarantees that the information sent to the central control station is simultaneously received by all mobile transfer units.